JP2010088591A - Ultrasonic probe and ultrasonograph using the same - Google Patents

Abstract

An ultrasonic probe capable of accurately measuring the surface temperature of an ultrasonic probe in real time without forming a large number of temperature sensors even in a probe having a large aperture such as a linear or convex probe.
SOLUTION: A backing material 111, a lower electrode group 112 formed on the backing material 111, in which a plurality of lower electrodes 112a are arranged, and one piezoelectric element 114a on each of the plurality of lower electrodes 112a. The piezoelectric element group 114 in which a plurality of piezoelectric elements 114a are arranged, the upper electrode 13 formed on the plurality of piezoelectric elements 114a, and the piezoelectric element 114a and the measurement object are formed on the upper electrode 13. An ultrasonic wave including a transducer 20 having a matching layer 115 that suppresses reflection of ultrasonic waves due to an acoustic impedance difference between the body and an acoustic lens 116 that focuses ultrasonic waves transmitted and received by the piezoelectric element 114a. The probe 10 includes a temperature sensor 21 connected to the upper electrode 13.
[Selection] Figure 2

Description

The present invention relates to an ultrasonic probe and an ultrasonic diagnostic apparatus using the ultrasonic probe, and more particularly to an ultrasonic probe including a transducer in which a plurality of piezoelectric elements are arranged and an ultrasonic diagnostic apparatus using the ultrasonic probe.

The ultrasonic diagnostic apparatus transmits an ultrasonic signal to a measurement object (for example, a human body), then receives an ultrasonic echo signal reflected by the measurement object, and converts it into an electrical signal converted from the ultrasonic echo signal. An ultrasonic image is provided on a monitor or the like by executing predetermined video processing. In such an ultrasonic diagnostic apparatus, an ultrasonic signal is transmitted to a measurement object, an ultrasonic echo signal reflected by the measurement object is received, and the received ultrasonic echo signal is converted into an electrical signal. In addition, an ultrasonic probe including a vibrator in which a plurality of piezoelectric elements are arranged is used (for example, see Patent Document 1).

Here, an example of an ultrasonic probe including a vibrator will be described. FIG. 3 is a perspective view illustrating a schematic configuration of an example of an ultrasonic probe including a transducer. 3 shows a case where the acoustic lens 116 and the matching layer 115 are attached only to the upper surface of a part of the piezoelectric elements 114a for easy understanding of the explanation. The matching layer 115 is attached so as to cover the upper surfaces of all the piezoelectric elements 114a.
The ultrasonic probe 100 includes a backing material 111, a lower electrode group 112 including M lower electrodes 112a formed on the backing material 111, and M pieces of M electrodes formed on the M lower electrodes 112a. A piezoelectric element group 114 including the piezoelectric elements 114 a, a GND line (upper electrode) 113 formed on the M piezoelectric elements 114 a, a matching layer 115 formed on the GND line 113, and a matching layer 115 are formed on the matching layer 115. The electrically connected acoustic lens 116, M lead wires (signal lines) 118a for electrically connecting the lower electrode group 112 and the flexible printed circuit board (FPC), and the GND wire 113 and the FPC are electrically connected. And a vibrator having a ground wire (common connection line) 119.

The backing material 111 is formed using ferrite rubber or the like, and has a function as a support and a function as an absorber that absorbs unnecessary ultrasonic waves radiated from the lower surface of the piezoelectric element 114a.
The piezoelectric element 114a is formed by using a piezoelectric ceramic such as PZT (Lead Zirconate Titanate) or the like, generates an ultrasonic signal in response to a transmission pulse signal that is an electrical signal, and is reflected by a measurement object. A sound echo signal is received, and the received ultrasonic echo signal is converted into an electrical signal.
Such a piezoelectric element 114a has a strip shape, and the M piezoelectric elements 114a are arranged in a row at a predetermined interval in the horizontal direction (X direction) (for example, the piezoelectric element group 114 has , 40 mm in the X direction).

One lower electrode 112a is formed of a metal such as silver on the lower surface of one piezoelectric element 114a. Furthermore, one lead wire 118a is electrically connected to one lower electrode 112a (for example, by wire bonding using a silver wire).
A GND line 113 is formed of a metal such as silver on the upper surface of the M piezoelectric elements 114a. The GND line 113 includes a linear first GND line 113a extending in the horizontal direction (X direction) and a linear second GND line 113b extending in the horizontal direction (X direction). The first GND line 113a is formed on the near side on the upper surface of the M piezoelectric elements 114a, and the second GND line 113b is formed on the back side on the upper surface of the M piezoelectric elements 114a.
That is, the first GND line 113a is commonly connected to the M piezoelectric elements 114a, and further, the ground wire 119 is electrically connected to the right side.

The matching layer 120 is formed of an epoxy resin or an organic resin in which metal particles such as W are dispersed, and thin films having different acoustic characteristics are laminated in two or three layers in the vertical direction (Z direction). It is comprised and it suppresses that an ultrasonic signal is reflected by the acoustic impedance difference between the piezoelectric element (20-30 MRayl) 114a and a measurement object (for example, 1.5 MRayl in the case of a human body). That is, the acoustic impedance value of each thin film is set so as to gradually decrease from the piezoelectric element 114a toward the measurement object.
The acoustic lens 116 is formed using silicon rubber or the like, and converges ultrasonic waves transmitted and received by the piezoelectric element 114a in the Y direction.

According to such an ultrasonic probe 100, when a transmission pulse signal is applied to the piezoelectric element 114a, an ultrasonic signal due to vibration of the piezoelectric element 114a is generated.
By the way, when the transmission pulse signal is applied to the piezoelectric element 114a, heat is generated in addition to the generation of an ultrasonic signal due to the vibration of the piezoelectric element 114a. Then, the surface temperature T of the ultrasonic probe 100 is increased by the generated heat. As a result, when the surface temperature T of the ultrasonic probe 100 becomes high, the ultrasonic probe 100 is used in contact with the measurement object. In some cases, the measurement object was damaged.

Therefore, according to the individual standard JIS T 0601-2-37 (IEC 60601-2-37), the surface temperature increase ΔT of the ultrasonic probe 100 is defined as follows.
(1) Body surface application (ambient temperature 23 ± 3 ℃)
Air standing test: Temperature rise ΔT ≦ 27 ° C
Mock use test: Temperature rise ΔT ≦ 10 ° C
(2) In-body use (ambient temperature 23 ± 3 ° C)
Air standing test: Temperature rise ΔT ≦ 27 ° C
Mock use test: Temperature rise ΔT ≦ 6 ℃

In addition, by measuring the surface temperature T of the ultrasonic probe 100 in advance under all driving conditions such as the driving voltage and the frequency of the transmission pulse signal and creating an empirical formula, the ultrasonic probe is obtained using the obtained empirical formula. There is also a prediction method for predicting a surface temperature T of 100. As a result, the surface temperature T of the ultrasonic probe 100 is predicted and controlled in real time.
JP 2007-215921 A

However, according to the individual standard JIS T 0601-2-37 and the prediction method as described above, the surface temperature T of the ultrasonic probe 100 must be measured in advance before inspecting the measurement object. There is a problem that labor is required.
Further, in the prediction method as described above, when the ultrasonic probe 100 is configured in a complicated manner, it is difficult to perform a thermal analysis of the ultrasonic probe 100, and as a result, the surface temperature T of the ultrasonic probe 100 is determined. I can no longer predict.

In addition, it is conceivable to form a temperature sensor in the ultrasonic probe 100 so as to actually detect the surface temperature T of the ultrasonic probe 100. However, when inspecting only the region of interest (ROI) of the measurement object, Since the transmission pulse signal is applied only to some (several to a dozen) piezoelectric elements 114a from among the M piezoelectric elements 114a, a temperature distribution is generated in the ultrasonic probe 100. It is necessary to form a large number of temperature sensors in the probe 100. As a result, since a large number of temperature sensors are formed on the ultrasonic probe 100, the number of lead wires 118a and the number of GND wires 113 must be reduced, which deteriorates the image quality of the obtained ultrasonic image.

In order to solve the above problems, the present inventors have studied a measurement method for accurately measuring the surface temperature of an ultrasonic probe in real time without forming a large number of temperature sensors on the ultrasonic probe. The heat generated by the piezoelectric element is made of rubber or the like for the backing material and has a low thermal conductivity (for example, 0.21 W / m · K), and the GND wire (upper electrode) and the lower electrode are made of silver or the like. Therefore, it was found that since the thermal conductivity (for example, 420 W / m · K) is high, it is hardly conducted to the backing material, but is conducted to the upper electrode and the lower electrode. Accordingly, it has been found that one or a few temperature sensors are formed so as to be electrically connected to the upper electrodes formed on the plurality of piezoelectric elements.

That is, the ultrasonic probe of the present invention includes a backing material that absorbs ultrasonic waves and a plurality of signal lines formed on the backing material so that one lower electrode is electrically connected to each of the signal lines. A lower electrode group in which lower electrodes are arranged; a piezoelectric element group in which a plurality of piezoelectric elements are arranged so that one piezoelectric element is formed on each of the plurality of lower electrodes; Ultrasonic waves are reflected by the difference in acoustic impedance between the piezoelectric element and the measurement object, formed on the piezoelectric element and formed on the upper electrode, which is a common electrode for the plurality of piezoelectric elements. An ultrasonic probe comprising a transducer having a matching layer that suppresses the vibration and an acoustic lens that is formed on the matching layer and focuses an ultrasonic wave transmitted and received by the piezoelectric element, the ultrasonic probe comprising: Contact So that comprising a temperature sensor.

According to the ultrasonic probe of the present invention, the temperature sensor connected to the upper electrode is provided.
By using the ultrasonic probe, when a transmission pulse signal is applied to the piezoelectric element, an ultrasonic signal is generated by vibration of the piezoelectric element. At this time, heat is generated in addition to generation of an ultrasonic signal due to vibration of the piezoelectric element. A large amount of heat generated in the piezoelectric element is detected by the temperature sensor by being conducted to the upper electrode as described above.

As described above, according to the ultrasonic probe of the present invention, the surface temperature can be accurately measured in real time without forming a large number of temperature sensors.

(Means and effects for solving other problems)
In the above invention, the plurality of piezoelectric elements are arranged in a row in a lateral direction, the temperature sensor is formed beside the piezoelectric element group, and the upper electrode is You may make it connect with the said temperature sensor by extending to the side of a piezoelectric element group.
According to the ultrasonic probe of the present invention, since the temperature sensor is not formed in front of the radiation surface of the piezoelectric element, the temperature sensor can be prevented from affecting the obtained ultrasonic image.

In the above invention, the temperature sensors are respectively formed on both sides of the piezoelectric element group, and the upper electrode is connected to the temperature sensors on both sides of the piezoelectric element group. May be.
According to the ultrasonic probe of the present invention, when inspecting only a region of interest (ROI) of a measurement object, a transmission pulse is transmitted to only some (several to tens of) piezoelectric elements from among a plurality of piezoelectric elements. When a signal is applied, the heat generated by the piezoelectric element is immediately detected by the nearer temperature sensor, so that the responsiveness of the detected temperature can be improved.

The ultrasonic diagnostic apparatus of the present invention may include an ultrasonic probe as described above and a control unit that controls the ultrasonic probe based on the temperature detected by the temperature sensor.
According to the ultrasonic diagnostic apparatus of the present invention, since the control unit can accurately measure the surface temperature of the ultrasonic probe in real time, the ultrasonic probe is controlled so as not to damage the measurement object. Can do. For example, when the detected temperature is equal to or higher than the set threshold temperature, the ultrasonic probe is automatically controlled so as to lower the drive voltage, slow the repetition frequency, or reduce the number of drive wave stations.

Furthermore, in the above invention, the maximum width of the opening of the ultrasonic probe is 35 mm or more, and the control unit observes the maximum temperature of the ultrasonic probe with two or less temperature sensors, whereby the ultrasonic wave The temperature of the probe may be controlled.
According to the ultrasonic diagnostic apparatus of the present invention, the maximum temperature of an ultrasonic probe can be observed with a small number of temperature sensors even with an ultrasonic probe having a large aperture such as a linear or convex probe.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

FIG. 1 is a block diagram illustrating a schematic configuration of an example of the ultrasonic diagnostic apparatus according to the embodiment. FIG. 2 is a perspective view illustrating a schematic configuration of an example of the ultrasonic probe according to the embodiment. In addition, the same code | symbol is attached | subjected about the thing similar to the ultrasonic probe 100. FIG.
The ultrasonic diagnostic apparatus includes an ultrasonic probe 10 that transmits and receives ultrasonic waves, a monitor 2 that displays an ultrasonic image, an input apparatus 3 that performs an input operation, and a control that controls the entire ultrasonic diagnostic apparatus. Part (computer) 40.

The ultrasonic probe 10 includes a backing material 111, a lower electrode group 112 including M lower electrodes 112a formed on the backing material 111, and M pieces of M electrodes formed on the M lower electrodes 112a. A piezoelectric element group 114 composed of the piezoelectric elements 114 a, a GND line (upper electrode) 13 formed on the M piezoelectric elements 114 a, a matching layer 115 formed on the GND line 13, and formed on the matching layer 115 The electrically connected acoustic lens 116, M lead wires (signal lines) 118a for electrically connecting the lower electrode group 112 and the flexible printed wiring board (FPC), and the GND wire 13 and the FPC are electrically connected. A vibrator 20 having a common connection line 19a made of metal, a temperature sensor 21, and two metal common connection lines 19b and 19c that electrically connect the temperature sensor 21 and the FPC.
The FPC to which the M lead wires 118a and the common connection lines 19a, 19b, and 19c are connected is connected to a computer 40 described later.

Temperature sensor 21 is comprised of a first temperature sensor 21a for detecting a first temperature T _1, the second temperature sensor 21b for detecting a second temperature T _2. The first temperature sensor 21 a is preferably a resistance temperature sensor proportional to the temperature of a thermistor or the like, and is formed on the right side of the piezoelectric element group 114. The second temperature sensor 21b is preferably a resistance temperature sensor proportional to the temperature of a thermistor or the like, and is formed on the left side of the piezoelectric element group 114. That is, the temperature sensor 21 is formed on both sides of the piezoelectric element group 114. Thereby, since the temperature sensor 21 is not formed in front of the radiation surface of the piezoelectric element group 114 (Z direction), the temperature sensor 21 can be prevented from affecting the obtained ultrasonic image.

On the upper surface of the M piezoelectric elements 114a, a GND line 13 is formed of a metal such as silver. The GND line 13 includes a linear first GND line 13a extending in the horizontal direction (X direction) and a linear second GND line 13b extending in the horizontal direction (X direction). The first GND line 13a is formed on the front side on the upper surface of the M piezoelectric elements 114a, and the second GND line 13b is formed on the rear side on the upper surface of the M piezoelectric elements 114a.
The first GND line 13a is connected in common to the M piezoelectric elements 114a, and further extends to the right side (X direction) to be electrically connected to the first temperature sensor 21a. Are connected to the second temperature sensor 21b by extending to the left side (X direction).
Accordingly, when only the region of interest (ROI) of the measurement object is inspected, when a transmission pulse signal is applied to only some (several) piezoelectric elements 114a from among the M piezoelectric elements 114a, the piezoelectric elements Since the heat generated in 114a is detected by the first temperature sensor 21a or the second temperature sensor 21b which is closer, the responsiveness of the detected temperatures T ₁ and T ₂ can be improved.

When the functions processed by the computer (control unit) 40 are described in a block form, an ultrasonic probe control unit 41 that controls the ultrasonic probe 10 and a monitor display control unit 42 that displays an ultrasonic image on the monitor 2 are provided.
The monitor display control unit 42 performs control to display an ultrasonic image on the monitor 2 based on an electrical signal from the ultrasonic probe 10 obtained via the FPC.

The ultrasonic probe control unit 41 sends the ultrasonic probe 10 via the FPC based on the temperature signals (temperatures T ₁ and T ₂ ) from the temperature sensor 21 obtained through the FPC and the control signal from the input device 3. Control.
Incidentally, as described above, if the surface temperature T of the ultrasonic probe 100 becomes too high, the measurement object may be damaged. In the present embodiment, the ultrasonic probe control unit 41 detects the first detected when any of the temperatures T ₁ or the second temperature T ₂ is equal to or greater than the set threshold temperature T _th is or lowering the driving voltage, or slow down the repetition frequency, so as to reduce the driving wave number of stations, ultrasonic The probe 10 is controlled.

Here, the set threshold temperature T _th set in the ultrasonic probe control unit 41 will be described.
A first temperature T ₁ of the second temperature T _2, a temperature of the first GND line 13a, not completely coincide with the surface temperature T of the ultrasonic probe 10. In other words, the surface temperature T of the ultrasonic probe 10, since the matching layer 115 and the acoustic lens 116 is formed, generally lower than the first temperature T ₁ of and the second temperature T _2. Therefore, by the user or the like before checking the measured object, it is calculated in advance the relationship between the surface temperature T and the first temperature T ₁ of the ultrasonic probe 10 and the second temperature T _2, the ultrasound probe controller A set threshold temperature T _th is set to 41.

As described above, according to the ultrasonic probe 10 of the present invention, the surface temperature of the ultrasonic probe 10 can be obtained only by forming the two temperature sensors 21 of the first temperature sensor 21a and the second temperature sensor 21b. T can be measured accurately in real time, and as a result, the ultrasonic probe 10 can be controlled so as not to damage the measurement object.

(Other embodiments)
(1) In the ultrasonic probe 10 described above, a configuration including a so-called linear array type piezoelectric element group 114 in which M piezoelectric elements 114a are arranged in a line on a plane has been shown. It is good also as a structure provided with what is called a convex array type piezoelectric element group arranged on the convex surface.
(2) In the ultrasonic probe 10 described above, the temperature sensor 21 is formed on both sides of the piezoelectric element group 114, but the temperature sensor is formed only on one side of the piezoelectric element group 114. It is good also as a structure.

The present invention can be used for an ultrasonic probe including a vibrator in which a plurality of piezoelectric elements are arranged.

1 is a block diagram illustrating a schematic configuration of an example of an ultrasonic diagnostic apparatus according to an embodiment. It is a perspective view showing a schematic structure of an example of an ultrasonic probe concerning an embodiment. It is a perspective view which shows schematic structure of an example of the conventional ultrasonic probe.

Explanation of symbols

10, 100 Ultrasonic probe 13, 113 GND wire (upper electrode)
19a, 19b, 19c, 119 Common connection line 20 Vibrator 21 Temperature sensor 111 Backing material 112 Lower electrode group 112a Lower electrode 114 Piezoelectric element group 114a Piezoelectric element 115 Matching layer 116 Acoustic lens 118a Lead wire (signal line)

Claims (5)

A backing material that absorbs ultrasound,
A lower electrode group in which a plurality of lower electrodes are arranged so that one lower electrode is electrically connected to each of a plurality of signal lines formed on the backing material;
A piezoelectric element group in which a plurality of piezoelectric elements are arranged so that one piezoelectric element is formed on each of the plurality of lower electrodes;
An upper electrode that is formed on the plurality of piezoelectric elements and is a common electrode for the plurality of piezoelectric elements;
A matching layer formed on the upper electrode and suppressing reflection of ultrasonic waves due to an acoustic impedance difference between the piezoelectric element and a measurement object;
An ultrasonic probe comprising a transducer formed on the matching layer and having an acoustic lens for focusing ultrasonic waves transmitted and received by the piezoelectric element;
An ultrasonic probe comprising a temperature sensor connected to the upper electrode. The plurality of piezoelectric elements are arranged in a row in the lateral direction,
The temperature sensor is formed beside the piezoelectric element group,
The ultrasonic probe according to claim 1, wherein the upper electrode is connected to the temperature sensor by extending to a side of the piezoelectric element group. The temperature sensors are respectively formed on both sides of the piezoelectric element group,
The ultrasonic probe according to claim 2, wherein the upper electrode is connected to temperature sensors on both sides of the piezoelectric element group. The ultrasonic probe according to any one of claims 1 to 3,
An ultrasonic diagnostic apparatus comprising: a control unit that controls the ultrasonic probe based on a temperature detected by the temperature sensor. The maximum width of the opening of the ultrasonic probe is 35 mm or more;
The ultrasonic diagnostic apparatus according to claim 4, wherein the control unit controls the temperature of the ultrasonic probe by observing the maximum temperature of the ultrasonic probe with two or less temperature sensors.

Images